A Bigger, Better Brain

Observations of animals as different as chimpanzees and dolphins are producing evidence of parallel types of intelligence in both, despite their vastly different morphology and native environments. One thing they have in common are uncommonly large brains when compared to their body sizes, a trait that is even more extreme in humans. The authors argue that these observations suggest that convergent evolution may have played a role in the development of humanlike intelligence in more than one recent evolutionary lineage.